SocketConnect (Function)

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Optimizing the connections for an IP address
Time-out
Connecting to an infrared port
Name resolution
Required permissions
Required application feature

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WINDEV Mobile

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See also

SocketConnect (Function)

In french: SocketConnecte

Connects a client computer to a given socket.

Notes:

UDP sockets: The UDP protocol being a "connectionless" protocol, SocketConnect cannot be used with the UDP protocol. To send or receive data with the UDP protocol, you must create a UDP socket (SocketCreateUDP) then send/receive data with the "special UDP" syntaxes of SocketWrite and SocketRead.
SSL sockets: To send or receive data with the SSL protocol, you must create an SSL socket (SocketCreateSSL) and connect to this socket with SocketConnectSSL.
Communication with robots or with non-WINDEV applications: To simplify the exchanges of data by socket, a transmission mode is initialized by default. For a communication with an external module (non-WINDEV application, robot, ...), this transmission mode can prevent the communications from operating properly. SocketChangeTransmissionMode is used to change this transmission mode (the SocketNoEndTag constant allows you not to modify the frames read and written).

Reminder: A socket is a communication resource used by the applications to communicate between computers regardless of the network type.

Versions 15 and later

This function is now available for the Android applications.

New in version 15

This function is now available for the Android applications.

Versions 17 and later

This function is now available for the iPhone/iPad applications.

This function is now available for the Windows Phone applications.

New in version 17

This function is now available for the iPhone/iPad applications.

This function is now available for the Windows Phone applications.

This function is now available for the iPhone/iPad applications.

This function is now available for the Windows Phone applications.

Versions 18 and later

This function is now available in Android Widget mode.

New in version 18

This function is now available in Android Widget mode.

Versions 23 and later

This function is now available in Universal Windows 10 App mode.

New in version 23

This function is now available in Universal Windows 10 App mode.

Example

IF SocketConnect("Server", 8000) = False THEN
Error("Connection error" + ErrorInfo(errMessage))
END

Syntax

Connecting to a socket Hide the details

<Result> = SocketConnect(<Socket Name> , <Port Number> [, <Address> [, <Maximum Time-out>]])

<Result>: Boolean

True if the function was successful,
False otherwise. To find out the error details, use ErrorInfo.

<Socket Name>: Character string (with quotes)

Name that will be given to the connection opened on the server socket. This name will be used by all socket functions.

<Port Number>: Integer

Port number of socket. If you are using a socket associated with a preset protocol, use the port number associated with the protocol.
If the socket was created by a WINDEV application, this number must be included between 5 000 and 65 000. In this case, the number must be identical to the port number specified in SocketCreate.

<Address>: Optional character string (with quotes)

Address of server. If this parameter is not specified, the server is sought on the current computer. This address can be given in the following format:
IP address in XXX.XXX.XXX.XXX format (125.5.110.100 for example).
URL containing the server name (www.windev.com for example). This syntax is recommended.

<Maximum Time-out>: Optional integer or optional Duration

Maximum time-out (in milliseconds) for establishing the connection. This time-out will be used if the server refuses the connection (SocketDeny). In this case, the connection will not be locking. This parameter can correspond to:
an integer corresponding to the number of milliseconds,
a Duration variable,
Versions 23 and later
the direct indication of duration (1 s or 10 ms for example).
New in version 23
the direct indication of duration (1 s or 10 ms for example).
the direct indication of duration (1 s or 10 ms for example).
This time-out is set to 5000 milliseconds by default (5 seconds). See remarks for more details.

Remarks

Optimizing the connections for an IP address

When an IP address is passed to SocketConnect, the connection can be optimized by using the following code:

Socket.Option = SocketOptimizeIPConnection

This option is not enabled by default because the connection may fail in some configurations. However, it may be useful in some applications for which the performances are critical.

Note: To restore the default operating mode, all you have to do is use the SocketOptionDefault constant:

Socket.Option = SocketOptionDefault

Time-out

The time-out specified by <Maximum Time-out> groups the time-out of two steps:

the time-out for address resolution: this time-out cannot be configured and it can be optimized (see below).
the maximum time-out for the connection to be accepted by the server. Several cases may occur:
- the server refuses the connection.
- the server accepts the connection within the time-out.
- the server is not available.
- the specified address is invalid.

To optimize the time-out for address resolution (time required to find the address), we advise you to:

use a DNS on the network. Therefore, this address will be sought toward this server and not for each computer (1 search instead of x searches where x represents the number of computers). Each computer must be registered toward this server.
for an IP address, use the Socket.Option variable as follows:

Socket.Option = SocketOptimizeIPConnection

This solution is not available.

Connecting to an infrared port

To connect to a socket that is using an infrared port:

Create a socket using the infrared port on the server (SocketCreateInfrared in a WINDEV application).
In the client application (WINDEV application), use SocketConnectInfrared to connect to this socket.

Name resolution

The Android emulator does not use the system of name resolution of the computer on which it is run. This detail is important if your development computer is configured to automatically add a suffix of domain name local to the computer names to resolve. In the Android emulator, the full names must be specified.

For example: If your computer is configured to add the "mydomain.com" suffix to the simple names, the following code:

SocketConnect("myserver")

will attempt to connect to myserver.mydomain.com if it is run directly on the PC and to "myserver" in the Android emulator.

Required permissions

The call to this function modifies the permissions required by the application.
Required permission : INTERNET
This permission allows the applications to open the network sockets.

Versions 23 and later

Required application feature

The use of this function triggers the declaration of an application feature in the wizard for generating the application.

Required feature: Family and corporate networks

This feature allows the applications to use incoming and outgoing accesses to the family and corporate networks.

New in version 23

Required application feature

The use of this function triggers the declaration of an application feature in the wizard for generating the application.

Required feature: Family and corporate networks

This feature allows the applications to use incoming and outgoing accesses to the family and corporate networks.

Required application feature

The use of this function triggers the declaration of an application feature in the wizard for generating the application.

Required feature: Family and corporate networks

This feature allows the applications to use incoming and outgoing accesses to the family and corporate networks.

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